In order to recognize the directionality of a sound signal, a user has to be able to recognize an interaural time difference (ITD) which is the difference between times that sound signals arrive at both ears of the user or an interaural level difference (ILD) which is the difference between the intensities of the sound signals arriving at both ears. However, a person who is hard of hearing has low sensitivity to the ITD and a high threshold of a sound signal and would feel difficulties recognizing the directionality of the sound signals based on the ITD or the ILD.
Accordingly, there is a growing need to develop a method of processing and outputting sound signals arriving at both ears so that even a person who is hard of hearing sound may recognize the directionalities of the sound signals.